南京地区城市化对陆地生态系统总初级生产力的影响

Impact of Urbanization on the Total Primary Productivity of Terrestrial Ecosystems in Nanjing Area

以南京地区为研究区域,基于多源遥感数据和降尺度植被生产力数据,分析了2000~2020年南京城市扩张进程及对总初级生产力(Gross Primary Productivity,GPP)直接影响的时空变化,同时分析了气候变化与城市化的间接效应对直接影响的补偿作用。结果表明,南京地区在2000~2020年城区范围出现明显扩张,不透水面的覆盖面积由620.31 km^(2)增长至2020年的1245.66 km^(2),增加了一倍以上。由于城市化强度提高,土地覆盖变化产生的直接影响导致南京城区GPP下降−345.98 g(C)m^(-2)a^(-1),而区域气候变化和城市化的间接效应使城区GPP增加298.67 g(C)m^(-2)a^(-1),抵消了直接效应的86.33%。城区范围内间接影响的增加趋势和贡献率高于郊区,证明城市环境促进了城区剩余植被生长。在全球变暖和城市化继续发展的背景下,了解城市扩张如何影响植被生产力有助于更好地应对全球变化挑战、推动构建生态文明城市,具有重要的现实意义和参考价值。

Based on multisource remote sensing data and downscaled vegetation productivity data,the spatiotemporal dynamics of urban expansion,its direct and indirect effects on Gross Primary Productivity(GPP)in Nanjing from 2000 to 2020 are investigated.Results reveal a considerable expansion of the urban area in Nanjing from 2000 to 2020,causing the doubling of the impervious surface from 620.31 km^(2)in 2000 to 1245.66 km^(2)in 2020.Due to the increase in urbanization intensity,the direct effect of land cover change caused a decrease of−345.98 g(C)m^(-2)a^(-1)in the GPP of Nanjing urban area,whereas the indirect effect of regional climate change and urbanization caused an increase of 298.67 g(C)m^(-2)a^(-1)in the GPP of Nanjing urban area,which offsets 86.33%of the direct effect.The increasing trend and contribution rate of indirect influences in urban areas exceed those in suburban areas,indicating that the urban environment encourages residual vegetation growth.In terms of the continuous expansion of major cities worldwide,characterizing and understanding the effects of urban expansion on vegetation productivity hold considerable practical significance and reference value in addressing global change challenges and advancing the construction of ecologically civilized cities.